Methods for lining the internal walls of a conduit for conveying fluid carrying marine fouling organisms with a liner of anti-fouling material

ABSTRACT

The internal walls of a conduit for conveying fluid carrying marine fouling organisms is lined with a liner of anti-fouling material by inserting an expandable liner of anti-fouling material into the conduit and by expanding the liner radially outwardly into tight engagement with the internal walls with sufficient force to prevent movement of the liner with respect to the conduit upon the fluid flowing therethrough. The liner of anti-fouling material prevents the marine fouling organisms from contacting the internal walls of the conduit and thereby prevents the marine fouling organisms from adhering to or collecting on the internal walls and thereby prevents such marine fouling organisms from constricting the flow of fluid through the conduit. The liner of anti-fouling material may be comprised of a plurality of generally annularly shaped and radially expandable bands of such material which are inserted into the conduit and aligned axially and adjacent each other. A plurality of bands of radially outwardly expandable material may be inserted into the bands of anti-fouling material and positioned over the adjacent edges of adjacent bands of anti-fouling material and expanded radially outwardly to force at least the underlying portions of the bands of anti-fouling material into tight engagement with the internal walls of the conduit and with sufficient force to prevent the bands of anti-fouling material to move with respect to the conduit upon the fluid flowing therethrough.

This is a division, of application Ser. No. 14,486 filed Feb. 23, 1979,now U.S. Pat. No. 4,257,459 issued Mar. 24, 1981.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to methods of and apparatus for liningthe internal walls of a conduit, and in particular it relates to methodsof and apparatus for lining the internal walls of a conduit forconveying fluid carrying marine fouling organisms with anti-foulingmaterial for preventing such marine fouling organisms from contactingthe internal conduit walls and thereby from adhering thereto andconstricting the flow of fluid through the conduit.

2. Description of the Prior Art

As is known to those skilled in the marine art, marine fouling organismswill eventually adhere to or collect on the surface of any objectexposed to the sea water. Such marine fouling organisms include allmarine growth capable of forming a more or less secure attachment to asurface exposed thereto, or which contribute a more or less adherentdeposit to a surface exposed thereto. Marine fouling organisms can bedivided into two groups, namely the group of uni-cellularmicro-organisms composed of many species of bacteria and other plantlife, and various types of protozoa, and the group of macro- ormulti-cellular organisms, both plant and animal. Such marine foulingorganisms include practically all of the marine bacteria, flora,invertebrate fauna present in sea water and especially include barnaclesand other marine crustaceans found in sea water.

As further known to those skilled in the marine art, sea water is usedas a coolant for steam condensers utilized in electrical generatingplants. The sea water is conveyed to and from the condensers by largediameter concrete pipes or conduits. Over a relatively short period oftime, marine fouling organisms carried by the sea water adhere to orcollect on the internal walls of the concrete pipes and constrict theflow of sea water through the pipes so severely that the electricalgenerating plant must be closed down for an extended period of timesufficient to permit the internal walls of the pipes to be mechanicallycleaned such as by scraping and/or air blasting. Since this cleaningoperation results in the electrical generating plant being shut down, itis enormously expensive and highly undesirable.

Various anti-fouling materials are known to the art which are capable ofpreventing marine fouling organisms from contacting the surfaceprotected by the liner and to which marine life does not substantiallyadhere. Such known anti-fouling materials include copper and variouscopper base alloys.

As reported in the reprint from POWER ENGINEERING MAGAZINE entitled,"Special Linings In Concrete Intakes Prevent Fouling From MarineGrowth," authored by Harold A. Todhunter, Mechanical Design Engineer,Los Angeles Dep-. of Water and Power, and which reprint is provided bythe International Nickel Co., Inc., 67 Wall Street, N.Y., N.Y. 10005,sheets of anti-fouling material, for test purposes, have been nailed tothe walls of a concrete intake to prevent fouling of the intake walls bymarine growth. The anti-fouling material used was a copper base alloy,viz., a 90-14 10 copper-nickel alloy, and the nails used were Inconel750X nails installed with Ramset guns. Obviously, such installation ofanti-fouling material requires that the concrete intake be drained andequally obvious is that such an installation would be undesirably timeconsuming and enormously expensive if used in conjunction with anoperating electrical generating plant because it would require theelectrical generating plant to be shut down during installation.

Accordingly, there exists a need in the art of an anti-fouling linerwhich may be readily and relatively inexpensively inserted inside of aconduit, e.g. a sea water conveying conduit, and which liner has thecapability of being inserted into the conduit while the sea water isstill present although the flow of sea water through the conduit mayhave to be temporarily halted or slowed. Thus, even if an associatedelectrical generating plant must be shut down, the shut down would beonly quite temporary and of a much shorter duration than required by theabove-noted prior art.

SUMMARY OF THE INVENTION

The anti-fouling liner of the present invention and the method of thepresent invention for inserting the same in a conduit, such as aconcrete conduit for conveying sea water carrying marine foulingorganisms, overcome the above-noted prior art problem by providing aradially outwardly expandable liner of anti-fouling material which maybe inserted into a conduit and expanded radially outwardly intoengagement with the internal walls of the conduit with sufficient forceto prevent the liner from moving with respect to the conduit upon theflow of fluid, e.g. sea water, therethrough. Such liner may include aplurality of generally annularly shaped and radially expandable bands ofanti-fouling material which may be inserted into the conduit and alignedaxially and adjacent each other, and a plurality of bands of radiallyoutwardly expandable material may be inserted into the bands ofanti-fouling material and positioned over adjacent edges of adjacentbands of anti-fouling material and expanded radially outwardly to forceat least the underlying portions of the bands of anti-fouling materialinto tight engagement with the internal walls of the conduit and withsufficient force to prevent the bands of anti-fouling material to movewith respect to the conduit upon the flow of fluid therethrough.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration, in perspective, of a conduitprovided with a liner in accordance with the teachings of the presentinvention and with portions of the sides of the elements shown beingbroken away for clarity of presentation;

FIG. 2 is a diagrammatic illustration, of one of the annular bandscomprising the liner of the present invention;

FIG. 3 is a diagrammatic illustration of a plurality of radially outwardexpandable bands for maintaining the bands comprising the liner of thepresent invention in engagement with the internal walls of the linedconduit; and

FIG. 4 is a diagrammatic illustration of one method of expanding thebands illustrated in FIG. 3 radially outwardly and for maintaining suchbands so expanded.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, there is shown a conduit indicated by generalnumerical designation 10 and having internal walls 12. The conduit 10may be, for example, a concrete pipe for conveying sea water to or fromthe steam condensers of an associated electrical generating plant andwhich sea water carries marine fouling organisms which, upon contactwith the internal walls 12, would adhere to or collect on the internalwalls 12 and in time severely constrict the flow of sea water throughthe conduit. Also illustrated in FIG. 1 is a liner according to thepresent invention and identified by general numerical designation 14.

The liner 14 may be comprised of a plurality of generally annularlyshaped bands of material, such as for example anti-fouling material, andwhich bands are indicated respectively by numerical designations 16a . .. 16i.

It will be further understood by way of example, and as illustratedindividually with regard to band 16c in FIG. 2, that each band 16 isprovided with a circumferential length C and an axial length A and thateach band is split across its entire axial length, as indicated at 18,to permit the bands to be expanded radially outwardly. Still referringto FIG. 2, it will be further understood that each of the bands 16terminates axially in a pair of spaced apart generally circulartransverse edges 20 and 22 and that each of the bands 16 has outer axialportions adjacent the generally circular transverse edges 20 and 22 andwhich portions are indicated by numerical designations 24 and 26. Itwill be understood that the split 18 and the axial portions 24 and 26illustrated in FIG. 2 are exaggerated in proportional size for clarityof presentation.

Referring again to FIG. 1, it will be understood that the radiallyoutwardly expandable bands 16a . . . 16i are inserted within the conduit10 and are aligned generally axially internally of the conduit adjacent,or juxtaposed, to each other with their respective adjacent generallycircular transverse edges 20 and 22 positioned adjacently and forminggenerally circular edge lines 30 transverse of the conduit 10. It willbe understood that in accordance with the teachings of the presentinvention such bands may be axially aligned adjacent each other, i.e.not in actual edge-to-edge contact but in close and slightly spacedrelationship, or such bands may be aligned axially with their respectivegenerally circular transverse edges 20 and 22 in abutting engagement,that is in actual contact. Such axial alignment of the bands whetheradjacent or in abutting engagement will depend upon variousconsiderations such as convenience and ease of axial alignment of thebands which may make some axial space therebetween permissible anddesirable, and especially for commercial considerations, and it will beunderstood that some axial space may be permitted between the respectivegenerally circular transverse edges 20 and 22 of the bands and that theliner according to the present invention will function as desired,particularly where the liner is made of anti-fouling material.

Referring now to FIG. 3, there is shown a plurality of generallyannularly shaped bands of material, such as for example annular bands ofsuitable cold worked copper-silicon alloy, which bands are indicated bynumerical designations 32a . . . 32c. It will be understood that each ofthe bands 32a . . . 32c is provided with a circumferential lengthsubstantially the same as the circumferential length C of the bands 16a. . . 16i but that the axial length of each band 32 is substantiallyless than the axial length A of the bands 16. It will be furtherunderstood that each of the bands 32, as indicated at 34, is splitacross its entire axial length to permit radially outward expansion ofthe bands. The bands 32a . . . 32e are inserted internally of theaxially aligned bands 16a . . . 16i with each of the bands 32 beingpositioned generally over one of the generally circular edge lines 30and overlying the outer axial portions 24 and 26 of the adjacent bands16 forming the edge line over which the band 32 is positioned. It willbe further understood that each of the bands 32, in accordance with thefurther teachings of the present invention, is expanded radiallyoutwardly to force at least the underlying outer axial portions 24 and26 of adjacent bands 16 into tight engagement with the internal walls 12of the conduit 10 and with sufficient force to prevent the bands 16 frommoving with respect to the conduit 10 upon fluid, such as sea water,flowing through the conduit.

Referring now to FIG. 4, there is illustrated diagrammatically a methodof expanding each radial band 32, with radial band 32a being shownindividually by way of example. An expander, indicated by generalnumerical designation 36, includes a pair of displaced blocks 38 and 40interconnected by a rod 42 fixedly secured to the upper block 40 andextending threadedly through the lower block 38 and in engagement with athreaded bore formed through the lower block 38. Each block is providedwith a pair of outwardly extending arms 44 and 46 the ends of which maybe inserted into holes or indentations formed in the inner surface ofthe band 32a for receiving the ends of the arms 44 and 46. Upon rotationof one direction being imparted to the rod 42, the rod is moved upwardlywith respect to the lower block 38 causing the blocks 38 and 40 to bemoved diametrically away from each other and in turn causing therespective arms 44 and 46 to expand the band 32a radially outwardly intotight engagement with the underlying axial portions 24 and 26 of axiallyaligned and adjacent pair of bands 16. After such radial expansion ofthe band 32a, a suitably sized wedge 50, of suitable material such asthe same material of which the bands 32 are formed, may be inserted intothe split 32 to maintain the band 32 in the radially outwardly expandedposition. Then, the rod 42 may be rotated in the opposite direction tomove the blocks 38 and 40 towards each other and to release therespective arms 44 and 46 from the annular band 32a.

Alternatively, each of the bands 32 may be provided with a turnbucklespanning the split 34 with the opposite ends of the turnbuckle beingsecured to portions of the annular band 32 adjacent the split 34. Uponrotation of the turnbuckle bolt the opposite ends of the turnbucklewould be forced away from each other thereby expanding the annular band32 radially outwardly whereupon a suitable wedge, such as wedge 50, maybe inserted within the split 34 to maintain the annular band 32 in itsradially outwardly expanded position.

In one embodiment of the present invention, conduit 10 was a length ofsteel reinforced concrete of 12 feet in diameter and each annular band16 was of anti-fouling material, i.e. a copper nickel alloy of 90%copper and 10% nickel by weight, and each band 16 had a circumferentiallength C of 40 feet, an axial length A of 37 inches and a thickness of0.025 inch. The annular bands 16 may have a thickness of from0.020-0.060 inch, and preferably a thickness of 0.40 inch. In the sameembodiment, the annular bands 32 were made of a copper-silicon alloy of97% copper and 3% silicon by weight and had a circumferential length Cof 37.45 feet, an axial length of 3 inches and were 0.025 inch thick.The bands 32 may have a thickness of from 0.125 inch to 0.375 inch andpreferably a thickness of 0.025 inch.

It will be further understood by those skilled in the art that when theannular bands 16 are made of copper (as they may be) or a copper alloyanti-fouling material, such as 90-10 copper-nickel alloy describedabove, and wherein the fluid flowing through the conduit 10 is sea watercarrying marine fouling organisms, that there will be a slow solution ofthe copper present in the copper or the copper base alloy sufficient toprevent growth of marine fouling organisms, such as barnacles andsimilar marine organisms, on the internal surfaces of the annular bands16. Hence, upon the annular bands 16 being of such anti-foulingmaterial, such material serves the dual purpose of preventing physicalcontact between marine fouling organisms and the internal walls 12 ofthe conduit 10 and providing a slow solution of copper sufficient toprevent growth of, adherence to or collection on, marine foulingorganisms on the internal surfaces of the bands 16. Hence, upon aconduit 10 being aligned with such anti-fouling liner in accordance withthe teachings of the present invention, sea water carrying marinefouling organisms, for example, may flow through such conduit forextremely lengthly periods of time without any constriction of the flowthrough the conduit.

In summary, it will be understood by those skilled in the art that theliner of the present invention, and the method of inserting the same,provide a liner, particularly of anti-fouling material, which may,comparatively, be readily, easily and inexpensively inserted in aconduit and, when the liner is of anti-fouling material, may be readily,easily and inexpensively inserted in a length of concrete pipe forconveying sea water carrying marine fouling organisms. Further, it willbe understood that the liner of the present invention, and the method ofinserting the same, particularly where the liner is of anti-foulingmaterial, may be inserted in a concrete pipe for conveying sea water toand from the steam condensers of associated electric generatingapparatus by divers operating under water in the sea water contained bythe conduit but that the flow of such sea water may have to betemporarily halted or slowed while the liner is inserted according tothe method of the present invention. But, due to the method of thepresent invention, such anti-fouling liner may be installed in a muchshorter time than may be anti-fouling liners known to the prior art andhence any associated electrical generating apparatus will be shut down,if at all, for only a comparatively short length of time therebyproviding an enormous advance in the anti-fouling liner art.

It will be still further understood by those skilled in the art thatmany variations and modifications may be made in the present inventionwithout departing from the spirit and the scope thereof.

What is claimed is:
 1. The method of lining the internal walls of a seawater conveying conduit with anti-fouling material which materialprevents marine fouling organisms carried by the sea water fromcontacting said internal walls and which material also upon exposure tosaid sea water provides a slow solution for substantially preventingsaid marine fouling organisms from adhering thereto, comprising thesteps of:providing a plurality of generally annularly shaped bands ofanti-fouling material, and providing each of said bands withpredetermined circumferential and axial lengths and with a split acrossthe entire axial length thereof to permit the radially outward expansionof the band, and terminating each of said bands axially in a pair ofspaced apart, generally circular transverse edges, each of said bandshaving predetermined outer axial portions adjacent said generallycircular transverse edges; inserting said plurality of bands ofanti-fouling material into said conduit and aligning said bands axiallyinternally of said conduit adjacent each other and positioning saidaligned bands of anti-fouling material with their respective adjacentgenerally circular transverse edges adjacent each other and therebyforming generally circular edge lines transverse of said conduit;providing a plurality of generally annularly shaped bands ofpredetermined material, providing each of said bands of predeterminedmaterial with a predetermined circumferential length substantially equalto the circumferential length of said bands of anti-fouling material andproviding said bands of predetermined material with an axial lengthsubstantially less than said axial length of said bands of anti-foulingmaterial, and providing said bands of predetermined material with asplit across the entire axial length thereof to permit said bands ofpredetermined material to be expanded radially outwardly; inserting saidbands of predetermined material into said axially aligned bands ofanti-fouling material and positioning each of said bands ofpredetermined material generally over one of said generally circularedge lines and overlying respective predetermined axial portions of saidadjacent bands of said anti-fouling material; expanding said bands ofpredetermined material radially outwardly to force at least saidrespective predetermined outer axial portions of said adjacent bands ofanti-fouling material into tight engagement with said internal walls ofsaid conduit and with sufficient force to prevent said bands ofanti-fouling material from moving with respect to said conduit upon saidfluid flowing therethrough; and maintaining said bands of predeterminedmaterial expanded radially outwardly.